I've been helping Jupiter Audio Research out on the side to help them dial in their finalized mod for the HD650. I think I just packed up about 10 iterations to finally send back. It's a mountain of HD650 drivers! (And one pair of HD600 drivers, which may or may not get a mod too.)

As a disclaimer, I was allowed to keep a pair of my choosing as a thank you for my testing and feedback. A loaner tour should be upcoming shortly once they get these pairs back and can make some last minute changes to send back out.

I think you have to buy these outright, i.e. may not be able to send your pair in (it's a logistics and dealing-with-customers sanity issue). TBD on JAR's end. I believe it will be about $400-450 for everything, including shipping. Apparently the custom made damping parts and all the silicone don't come cheap.

Final mod technical details:

- Same huge damping piece on back, but filled to the brim with silicone. Tightly bolted onto the enclosure. Silicone makes damping contact around the perimeter of the enclosure and across the driver on top of the magnet.

- Foam behind driver, previously in spider, has been reduced to a single, thin piece.

- There is silicone filling on the top, bottom, and side portions of the front side of the enclosure, under the pads.

- Front foam cutout is a little larger than seen in normal mods. Cutout is same diameter as driver in full and exposes that area as such.

One caveat is that the final pair I have just lightly stuffs this piece of rear foam in the magnet opening area. What you get from JAR will actually be wedged under the big damping piece. This shouldn't change the sound in a meaningful way, so I feel comfortable talking about these as-is, as does Jupiter Audio Research.

Side note, for anyone that heard this pair at RMAF, it did not have the rear and front foam tweaks as mentioned above.

Sound Impressions

- General frequency response is very similar to that of a newer, stock HD6XX. But that hint of strain, the mildest hint of low-treble stridency, etc. have been opened up and smoothed out.

- Sounds more dynamic and controlled overall. Looseness, and that strain I mentioned, seem alleviated through said improvements in control and focus. (Sense of dynamics more closely matches that of HD650s from a few years back, since newer pairs are a little more damped and HD600-ish sounding.)

- Through this refinement, details across the board, top to bottom, seem easier to pick out.

- Background seems blacker, though that's a bit hard to explain and quantify on headphones vs. amps and DACs.

- Bass is less bloomy. Tighter, faster, better defined overall. But note that it's still an HD650.

Really, it seems to combine the pros from stock pairs and fully modded pairs, the kind without any foam behind the driver, while cancelling out most of the cons of each (within limitations of what the HD650's driver can do). It's easiest to just reiterate that these retain the balance of the stock HD650 but add a whole new layer of refinement and control and conventional mods haven't quite yet reached.

Measurements

NOTE: All references in measurements to "3L" or "3L Tweaked" refer to the final JAR HD650 mod. That was simply the label given on the driver to differentiate it from other iterations, and the "tweak" is what made it as the final cut. So these are all final results. I'm just too lazy to have to re-do all the images and relabel them.

Frequency response results look pretty darn similar to a stock HD6XX pair. Both used the exact same pads and headband to ensure consistency. The main differences seem to be a very subtle boost below 100Hz and a very subtle softening of the treble, most notable, though still very subtle, at 5KHz.

I had to double check these because of how similar these are, but, honestly, I think this is a good thing. Again, this was mostly dialed in by using just a little foam behind the driver and cutting out more of the front foam. The big damping piece does a surprising amount of work affecting how you tune the headphone.

1KHz at 90dB, on my modest rig, honestly looks pretty darn similar to that of a stock HD6XX (see attachment below for convenience). It is what it is.

CSD results show some interesting changes. Now, these are just captures of one set of measurements, not averages as seen in the FR and distortion results. But I was able to consistently show improvements in decay on the final JAR HD650 mod. The HD650/6XX already does extremely well here, but the JAR HD650 goes and cleans things up a bit further.

HD6XX CSDs for comparison.

HD6XX distortion for comparison. Very similar.

It's interesting how similar the results are between the JAR HD650 mod and stock HD6XX. CSDs are the biggest clue that we're seeing some benefits from the mods, at least on my rig. Yet, in listening, improvements are obvious, as they would be in any HD650 mod. But this one in particular probably takes HD650 damping far beyond anything I've seen with Dynamat and adhesive foam. So, it makes sense that this is probably the most controlled sounding HD650 I've heard.

"What the heck are you gonna do if you're on a picnic and have an ice cream, and the ants crawl on the ice cream? What are you gonna do? You're gonna eat the ants, because it's made out of protein. For your health!" - Dr. Steve Brule

I've been helping Jupiter Audio Research out on the side to help them dial in their finalized mod for the HD650. I think I just packed up about 10 iterations to finally send back. It's a mountain of HD650 drivers! (And one pair of HD600 drivers, which may or may not get a mod too.)

As a disclaimer, I was allowed to keep a pair of my choosing as a thank you for my testing and feedback. A loaner tour should be upcoming shortly once they get these pairs back and can make some last minute changes to send back out.

I think you have to buy these outright, i.e. may not be able to send your pair in (it's a logistics and dealing-with-customers sanity issue). TBD on JAR's end. I believe it will be about $400-450 for everything, including shipping. Apparently the custom made damping parts and all the silicone don't come cheap.

Final mod technical details:

- Same huge damping piece on back, but filled to the brim with silicone. Tightly bolted onto the enclosure. Silicone makes damping contact around the perimeter of the enclosure and across the driver on top of the magnet.

- Foam behind driver, previously in spider, has been reduced to a single, thin piece.

- There is silicone filling on the top, bottom, and side portions of the front side of the enclosure, under the pads.

- Front foam cutout is a little larger than seen in normal mods. Cutout is same diameter as driver in full and exposes that area as such.

One caveat is that the final pair I have just lightly stuffs this piece of rear foam in the magnet opening area. What you get from JAR will actually be wedged under the big damping piece. This shouldn't change the sound in a meaningful way, so I feel comfortable talking about these as-is, as does Jupiter Audio Research.

Side note, for anyone that heard this pair at RMAF, it did not have the rear and front foam tweaks as mentioned above.

Sound Impressions

- General frequency response is very similar to that of a newer, stock HD6XX. But that hint of strain, the mildest hint of low-treble stridency, etc. have been opened up and smoothed out.

- Sounds more dynamic and controlled overall. Looseness, and that strain I mentioned, seem alleviated through said improvements in control and focus. (Sense of dynamics more closely matches that of HD650s from a few years back, since newer pairs are a little more damped and HD600-ish sounding.)

- Through this refinement, details across the board, top to bottom, seem easier to pick out.

- Background seems blacker, though that's a bit hard to explain and quantify on headphones vs. amps and DACs.

- Bass is less bloomy. Tighter, faster, better defined overall. But note that it's still an HD650.

Really, it seems to combine the pros from stock pairs and fully modded pairs, the kind without any foam behind the driver, while cancelling out most of the cons of each (within limitations of what the HD650's driver can do). It's easiest to just reiterate that these retain the balance of the stock HD650 but add a whole new layer of refinement and control and conventional mods haven't quite yet reached.

Measurements

NOTE: All references in measurements to "3L" or "3L Tweaked" refer to the final JAR HD650 mod. That was simply the label given on the driver to differentiate it from other iterations, and the "tweak" is what made it as the final cut. So these are all final results. I'm just too lazy to have to re-do all the images and relabel them.

Frequency response results look pretty darn similar to a stock HD6XX pair. Both used the exact same pads and headband to ensure consistency. The main differences seem to be a very subtle boost below 100Hz and a very subtle softening of the treble, most notable, though still very subtle, at 5KHz.

I had to double check these because of how similar these are, but, honestly, I think this is a good thing. Again, this was mostly dialed in by using just a little foam behind the driver and cutting out more of the front foam. The big damping piece does a surprising amount of work affecting how you tune the headphone.

CSD results show some interesting changes. Now, these are just captures of one set of measurements, not averages as seen in the FR and distortion results. But I was able to consistently show improvements in decay on the final JAR HD650 mod. The HD650/6XX already does extremely well here, but the JAR HD650 goes and cleans things up a bit further.

It's interesting how similar the results are between the JAR HD650 mod and stock HD6XX. CSDs are the biggest clue that we're seeing some benefits from the mods, at least on my rig. Yet, in listening, improvements are obvious, as they would be in any HD650 mod. But this one in particular probably takes HD650 damping far beyond anything I've seen with Dynamat and adhesive foam. So, it makes sense that this is probably the most controlled sounding HD650 I've heard.

Click to expand...

Whats the weight addition of all this damping? Hope its not much more than 300g

I only heard the KISS mod briefly, but this should sound tighter and more controlled throughout the spectrum, more refined, any remaining areas of strain relieved.

"What the heck are you gonna do if you're on a picnic and have an ice cream, and the ants crawl on the ice cream? What are you gonna do? You're gonna eat the ants, because it's made out of protein. For your health!" - Dr. Steve Brule

Eh, a bit hard to explain, but just something I've found inherent to most 650s. I think it's the subtle 5Khz peak, very mild ringing there, possibly a hot spot above 10khz, and and overall sense that full dynamics and perfect treble timbre are being held back, can't open up, in a stock config. A tad overdamped in a way?

Going back and forth between a properly modded pair should make this more obvious.

"What the heck are you gonna do if you're on a picnic and have an ice cream, and the ants crawl on the ice cream? What are you gonna do? You're gonna eat the ants, because it's made out of protein. For your health!" - Dr. Steve Brule

Was considering ordering an HD6XX, but this mod has me curious given it seems to avoid what I hated about the old trifecta of mods, but having the front of the driver completely exposed is worrisome. Do either of you have pictures of what the finalized mod looks like inside the cups? Will there be an SBAF loaner tour for the finalized mod?

"Wherefore, do not spend money for that which is of no worth, nor your labor for that which cannot satisfy." - 2 Nephi 9:51

JAR650 or JMod is the name given to a HD650 modded by Jupiter Audio Research (JAR). JAR is run by the DIYer/modder, who goes by the name Jupiter, and is located in Korea. A new set of JAR650/Jmod can be purchased from JAR for $400, or you could send your own 650 in and have it modded for $100.

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@Jinxy245 Does ext1 have a website yet? Been putting off getting HD650/6XXs because of this )

I think you have to buy these outright, i.e. may not be able to send your pair in (it's a logistics and dealing-with-customers sanity issue). TBD on JAR's end. I believe it will be about $400-450 for everything, including shipping. Apparently the custom made damping parts and all the silicone don't come cheap.

Click to expand...

"Wherefore, do not spend money for that which is of no worth, nor your labor for that which cannot satisfy." - 2 Nephi 9:51

What's his website? Do I need to read Korean?Is this one of those mods that will take another two years to not be sold?

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id like to know as well. how to reach JAR?

and if my hd650 pair still has its foam behind the driver hole, and only slight dynamat where I could on the plastic surrounding the drivers, do I need to remove the dynamat before sending my pair to JAR?

What's his website? Do I need to read Korean?Is this one of those mods that will take another two years to not be sold?

Click to expand...

No website yet. He is a pretty quiet member of Head-Fi overall, and he just joined here...his handle on both sites is @ext1 so that' probably the best way to reach him right now.
edit: no need for Korean either, he speaks better English than many people I work with.

If a picture is worth a thousand words, then a demo is worth a thousand reviews

Sorry everyone! My bad for the confusion. @zonto Here are some pics-
That's how the inside looks like. What's that? Take off the earpads?
What's under that foam dammit!
Tada. Here is another old picture of when Hands and I were deciding on the exact dimension of foam cut.
So as you can see, the 3D part is bolted with screws to ensure very very tight fit and pressure. Helps a lot for the dampening!
And for the dust...well...personally I've not had any problems, and I don't keep my pair under a dust cover. But of course, there might be people with even dustier environments...so you can choose to insert foam piece without cutout, or any screen material of your choosing.

@purr1n I'm sorry for that- I'm in reality just an university student that just happened to have a lot of interest in headphones to stubbornly keep modding the 650, and just a dude who was so very fortunate to have had to opportunity to be noticed by Hands, so I don't have a website yet! I'd rather be very upfront with you all here than to assume some sort of fake posh company position (the name is more of a inhouse joke). I have a friend who's working on getting me a website, though.

Anyway that hasn't stopped some people from asking me for pairs- so I shipped out the loaner pair to Hands yesterday (currently it's in Italy) and another one to a member here. I'm not sure about the exact loaner details yet. Shipping I found out wasn't too bad. It's 40 bucks for Fedex express (1-3 days speed). That shipping rate has been quite helpful to my poor student wallet.

Any questions I'd be very happy to answer. Thank you all for the interest, it's really been so awesome to see so many people excited about the 650 like this! And of course, it's really not all my work, I have a lot of others to thank as well for sure.

@ext1 is it possible to get the mod without the front spider removed? I tend to poke my finger into that area somewhat regularly when taking off the headphone.

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You mean these guys?
Yes, of course you can opt to just leave them there. The driver membrane is tougher than you think by the way, even if you crush it you can just pop it back to shape really easily, so no worries either way.